| /** |
| * |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.openejb.core.mdb; |
| |
| import javax.jms.Connection; |
| import javax.jms.ConnectionFactory; |
| import javax.jms.DeliveryMode; |
| import javax.jms.Destination; |
| import javax.jms.JMSException; |
| import javax.jms.Message; |
| import javax.jms.MessageConsumer; |
| import javax.jms.MessageProducer; |
| import javax.jms.Session; |
| import javax.jms.ObjectMessage; |
| import java.lang.reflect.InvocationHandler; |
| import java.lang.reflect.Method; |
| import java.lang.reflect.Proxy; |
| import java.util.UUID; |
| import java.util.Map; |
| import java.util.TreeMap; |
| import java.io.Serializable; |
| |
| public class MdbProxy { |
| @SuppressWarnings({"unchecked"}) |
| public static <T> T newProxyInstance(Class<T> type, ConnectionFactory connectionFactory, String requestQueueName) throws JMSException { |
| ClassLoader classLoader = Thread.currentThread().getContextClassLoader(); |
| if (classLoader == null) classLoader = type.getClassLoader(); |
| if (classLoader == null) classLoader = ClassLoader.getSystemClassLoader(); |
| |
| InvocationHandler invocationHandler = new MdbInvocationHandler(connectionFactory, requestQueueName); |
| Object proxy = Proxy.newProxyInstance(classLoader, new Class[]{type}, invocationHandler); |
| return (T) proxy; |
| } |
| |
| public static void destroyProxy(Object proxy) { |
| InvocationHandler handler = Proxy.getInvocationHandler(proxy); |
| if (handler instanceof MdbProxy) { |
| MdbInvocationHandler mdbInvocationHandler = (MdbInvocationHandler) handler; |
| mdbInvocationHandler.destroy(); |
| } |
| } |
| |
| private static class MdbInvocationHandler implements InvocationHandler { |
| private static final int MAX_RESPONSE_WAIT = 1000; |
| private Connection connection; |
| private Session session; |
| private MessageProducer producer; |
| |
| public MdbInvocationHandler(ConnectionFactory connectionFactory, String requestQueueName) throws JMSException { |
| // open a connection |
| connection = connectionFactory.createConnection(); |
| connection.start(); |
| |
| // create a session |
| session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE); |
| |
| // create the request queue |
| Destination requestQueue = session.createQueue(requestQueueName); |
| |
| // create a producer which is used to send requests |
| producer = session.createProducer(requestQueue); |
| producer.setDeliveryMode(DeliveryMode.NON_PERSISTENT); |
| } |
| |
| public synchronized void destroy() { |
| MdbUtil.close(producer); |
| producer = null; |
| MdbUtil.close(session); |
| session = null; |
| MdbUtil.close(connection); |
| connection = null; |
| } |
| |
| private synchronized Session getSession() { |
| return session; |
| } |
| |
| public synchronized MessageProducer getProducer() { |
| return producer; |
| } |
| |
| public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { |
| Session session = getSession(); |
| if (session == null) throw new IllegalStateException("Proxy has been destroyed"); |
| |
| // create request |
| Map<String,Object> request = new TreeMap<String,Object>(); |
| String signature = MdbUtil.getSignature(method); |
| request.put("method", signature); |
| request.put("args", args); |
| |
| // create a new temp response queue and consumer |
| // this is very inefficient, but eliminates a whole class of errors |
| Destination responseQueue = session.createTemporaryQueue(); |
| |
| // Create a messages |
| ObjectMessage reqMessage = session.createObjectMessage(); |
| reqMessage.setJMSReplyTo(responseQueue); |
| String correlationId = UUID.randomUUID().toString(); |
| reqMessage.setJMSCorrelationID(correlationId); |
| reqMessage.setObject((Serializable) request); |
| |
| // Send the request |
| getProducer().send(reqMessage); |
| |
| // Wait for a message |
| // Again this is quite inefficient |
| MessageConsumer consumer = session.createConsumer(responseQueue); |
| try { |
| // wait for the message |
| Message message = consumer.receive(MAX_RESPONSE_WAIT); |
| |
| // verify message |
| if (message == null) throw new NullPointerException("message is null"); |
| if (!correlationId.equals(message.getJMSCorrelationID())) { |
| throw new IllegalStateException("Recieved a response message with the wrong correlation id"); |
| } |
| if (!(message instanceof ObjectMessage)) throw new IllegalArgumentException("Expected a ObjectMessage response but got a " + message.getClass().getName()); |
| ObjectMessage resMessage = (ObjectMessage) message; |
| Serializable object = resMessage.getObject(); |
| if (object == null) throw new NullPointerException("object in ObjectMessage is null"); |
| if (!(object instanceof Map)) { |
| if (message instanceof ObjectMessage) throw new IllegalArgumentException("Expected a Map contained in the ObjectMessage response but got a " + object.getClass().getName()); |
| } |
| Map response = (Map) object; |
| |
| // process results |
| boolean exception = response.containsKey("exception"); |
| Object returnValue = response.get("return"); |
| if (exception) { |
| throw (Throwable) returnValue; |
| } |
| return returnValue; |
| } finally { |
| MdbUtil.close(consumer); |
| } |
| } |
| } |
| |
| private MdbProxy() { |
| } |
| } |